This invention relates to an automatic valve for controlling the passage of an in-feed pressure fluid to be delivered in predetermined quantities into a receiver. When e.g. a traffic surface, cultivations or installations in a manufacturing plant have to be temporarily supplied with a predetermined quantity of liquid by means of several receivers (e.g. nozzles) at certain time intervals or in accordance with the prevailing circumstances and conditions, a liquid feed device is required the feed line of which has to be adapted to the total number of the receivers to be supplied with liquid, or each individual or several groups of receivers have to be equipped with comparatively expensive control elements, such as magnet valves, pressure air valves, control valves with time-signal transmitters or pressure pick-offs, all of which are susceptible to malfunction. When e.g. a traffic surface has to be temporarily sprinkled with water in order to cool it up during the warm season or with a liquid thaw means to prevent a glazed frost during the winter season, there are required several distribution nozzles and a correspondingly large feed device of the required quantity liquid with respectively dimensioned feed lines; all this represents respectively high investment costs. When such a feed device has to be switched on only at certain time intervals and only for a very short time, the operation of such a device is too expensive and the operating risk is too high.
There are several valves at disposal to control the delivery of the liquid mediums into a receiver, such as relieve pressure valves, shut-off valves, high-pressure valves, pilot valves or minimum pressure valves. There have been used e.g. minimum pressure valves which allow when opened the medium to flow to the receiver only at the moment when a predetermined, adjustable pressure has been reached, and which close at the moment when the pressure drops under a certain value. The piston of such a valve is loaded with a pressure coil which is adjustable to the required pressure of the medium by means of a pressure adjusting screw.
The problem as stated further on cannot, however, in any way be solved by the above-mentioned sorts of valves.